What function has real zeros at x=3 and x=7

Zero's are defined as places where a function crosses the y-intercept. Surprisingly, we don't need to do any calculations; since we already have the zero's, we can write our equation in the factored form of (x-3)(x-7). This is because when putting a 3 or 7 as x for one of the parts of the polynomial, it will equal zero. Expand this equation to get 

 or (x-3)(x-7).

:)

The correct answer is  b)